Kirill Abrams

Kirill Abrams's personal blog

Founder & CEO, UmbrellaX TOO

This is where I write about end-to-end encryption, post-quantum cryptography, jurisdictional risk, and the design decisions behind UmbrellaX. Personal opinions, not press releases.

More about me .com

Private messaging briefings

I compare private messengers by phone number identity, metadata exposure, end-to-end encryption defaults, backups, jurisdiction, and usable scale.
What I cover
  • messenger without phone number
  • private messenger metadata
  • secure WhatsApp alternative
  • Telegram alternative encrypted by default
A person reviews a diagram separating Signal delivery queues from message history on personal devices.
Private messaging

Does Signal store messages? Server storage

Does Signal store messages? Learn what its servers queue, where message history remains, and how backups and legal requests change the privacy boundary.

Sep 17 guide 5 min New
A person enters a Signal registration-lock PIN while setting up a replacement phone.
Private messaging

Signal registration lock: what it protects and costs

Signal registration lock adds a PIN to re-registration. Learn what it protects, its seven-day recovery cost, and the account boundary it cannot remove.

Sep 12 guide 5 min New
A person checks a contact-joined notification on a phone during a commute.
Private messaging

Does Signal notify contacts when you join? The privacy answer

Does Signal tell your contacts you joined? Learn what their apps can see, how local contact-join alerts work, and what number-based identity still exposes.

Sep 3 guide 5 min New
A person starts a separate Telegram Secret Chat while sitting on an outdoor bench.
Private messaging

Telegram Secret Chat: what it protects and misses

Telegram Secret Chats add end-to-end encryption and self-destruct tools, but stay tied to two devices. A founder's guide to the real tradeoff.

Sep 1 guide 5 min New
A person adjusts WhatsApp privacy controls at home.
Private messaging

WhatsApp privacy settings: what to change first in 2026

A founder's practical WhatsApp privacy settings guide: what to switch on, what each control protects, and which risks settings cannot remove.

Aug 27 guide 5 min New
Two colleagues compare Signal and Telegram messaging defaults at a shared table.
Private messaging

Signal vs Telegram privacy: what actually changes

Signal vs Telegram privacy is not a feature checklist. Compare encryption defaults, cloud sync, phone numbers, contact discovery, and the tradeoffs that remain.

Aug 25 comparison 5 min New
A person reviews the difference between Signal registration and sharing a username.
Phone number

Can you use Signal without a phone number? (2026)

Can you use Signal without a phone number in 2026? The current answer, what usernames change, and the privacy boundary an account model still keeps.

Aug 20 guide 5 min New
A person examines four separate phone-number privacy boundaries on a tablet.
Phone number

Phone number privacy in messaging apps: the real test

Hiding a number is only the first privacy setting. A founder's guide to visibility, discovery, recovery, and choosing a stronger messenger.

Aug 13 guide 5 min New
A person reads an account warning after a mobile-number reassignment.
Private messaging

SIM swap attack and secure messaging accounts

A founder guide to SIM swap attacks, messaging-account takeover risk, prompt containment, and why UmbrellaX refuses a carrier-controlled account root.

Aug 11 guide 5 min New
Two people deliberately exchange messaging usernames at a first meeting.
Private messaging

Messaging app usernames: privacy test

A founder's guide to messaging app usernames, phone-number privacy, contact discovery, and why UmbrellaX treats usernames as identity UX.

Aug 4 guide 5 min New
A person reviews a diagram of the different layers of messaging identity.
Private messaging

Anonymous messaging app: identity layers guide

A founder's guide to anonymous messaging apps: account identity, contact paths, network exposure, recovery, groups, and operator trust.

Jul 7 guide 5 min New
Two people consider a disappearing-message timer and the limits of deleting copies.
Private messaging

Disappearing messages privacy: what they miss

A founder's guide to disappearing messages privacy: screenshots, backups, metadata, groups, and why UmbrellaX treats deletion as a limit.

Jul 2 guide 5 min New
Two people compare identity, metadata, group and recovery criteria on a tablet.
Private messaging

Best encrypted messaging app: privacy test

A founder's 2026 guide to the best encrypted messaging app, with a privacy test for phone numbers, metadata, groups, jurisdiction, and UmbrellaX.

Jun 25 comparison 5 min New
An older adult holds a recovery-key card beside a phone restoring an encrypted backup.
Backups

Encrypted chat backups: recovery privacy test

A founder's guide to encrypted chat backups, cloud restore, recovery keys, and why UmbrellaX separates account recovery from message history.

Jun 18 guide 5 min New
A person on a sofa tries a labelled identity-design preview with a handle and no phone-number field.
Phone number

Messenger without phone number: privacy case

A founder's guide to phone numbers as identity, why they expose more than message content, and why UmbrellaX does not start from a telecom identifier.

May 21 guide 5 min New
Two people compare SimpleX pairwise connections with the planned UmbrellaX account model on printed cards.
Private messaging

UmbrellaX vs SimpleX: private messaging, no identifiers, and usable scale

SimpleX is radical about no identifiers. UmbrellaX is stronger as a default private messenger for groups, recovery, speed, jurisdiction, and normal use.

May 18 comparison 5 min New
A person compares WhatsApp phone-number registration with the pre-launch UmbrellaX identity design.
Private messaging

UmbrellaX vs WhatsApp: private messaging without Meta or phone number identity

UmbrellaX is stronger than WhatsApp for private messaging when Meta ownership, phone number identity, metadata, backups, and jurisdiction matter.

May 18 comparison 5 min New
A traveller compares Session onion routing with the planned UmbrellaX operator model on a tablet.
Private messaging

UmbrellaX vs Session: two answers to the no phone number question

UmbrellaX and Session both refuse phone number identity. Session went random Account IDs, onion routing, decentralised. UmbrellaX went MLS, post quantum, Kazakhstan. Five axes compared honestly.

May 10 comparison 5 min New
Two people compare Signal and UmbrellaX operator jurisdictions on printed cards.
Private messaging

UmbrellaX vs Signal: honest comparison by the founder of UmbrellaX

UmbrellaX outperforms Signal on groups, jurisdiction, phone number independence, and scale. Signal has a longer legacy record, but UmbrellaX is stronger for my threat model.

Apr 28 comparison 5 min New
A person compares Telegram cloud and secret chats with the planned UmbrellaX encrypted-group defaults.
Private messaging

UmbrellaX vs Telegram: encryption by default, jurisdiction, and private messaging

UmbrellaX encrypts every chat end to end by default; Telegram does not. UmbrellaX runs from Kazakhstan, Telegram from the UAE after a French arrest. Concrete comparison by the founder of UmbrellaX.

Apr 28 comparison 5 min New